Traffic signals for regulating the flow of traffic upon roadways are well known. Common examples of such traffic signals include stop signs, yield signs and speed limit signs, as well as a plurality of other signs and the like which are intended to control traffic and/or to provide helpful directions.
Of these various different traffic control signs, stop signs are particularly important because failure to obey a stop sign is especially likely to result in an automobile accident. Such automobile accidents frequently result in undesirable automobile damage, personal injury and/or death. Of course, the failure to obey various other traffic control signs and the like also frequently results in such automobile accidents.
Occasionally, the failure to obey such critical traffic control signs results from a difficulty or inability to see the traffic control sign. Sometimes not seeing such traffic control signs results from nearby distractions, which cause the driver to pay attention to something other than the traffic control sign. Other times, the traffic signs may be partially obstructed by foliage, or the driver may merely be inattentive. In any instance, drivers occasionally overlook critical traffic control signs and thereby risk automobile damage, personal injury and death.
Further, the ability of a driver to see traffic control signs and the like is generally dependent upon the ambient lighting conditions. For example, traffic control signs are substantially more difficult to see during periods of darkness or near darkness as well as during adverse weather conditions, e.g., overcast, fog, rain, sleet or snow.
Contemporary stop signs having LEDs formed thereon are known. For example, clusters of LEDs are being used to replace the red incandescent lights in the traffic signals, where 300 or more LEDs are clustered together to provide sufficient brightness. Such contemporary illuminated signs have been used by the prior art in an attempt to mitigate the above described problems associated with the difficulty or inability to see stop signs during darkness, near darkness and adverse weather conditions. However, such contemporary illuminated stop signs utilize LEDs which have a typical brightness of 1,500 millicandella or less and which thus do not contribute substantially to enhancing the visibility of the stop sign. Further, the total included radiation pattern angle of the LED clusters in such contemporary illuminated stop signs is generally greater than 20 degrees, thus undesirably reducing their effectiveness to be visible at a distance or in adverse conditions.
Those skilled in the art will appreciate that the ability of LEDs to contribute to enhancing the visibility of a stop sign or the like is dependent upon the brightness of the LEDs and also the radiation pattern angle thereof. Greater brightness provides more light, thus making the LEDs easier to see. A smaller radiation angle concentrates the available light, again making the LEDs easier to see.
In view of the foregoing, it is desirable to provide traffic signals having enhanced visibility, so as to enhance the likelihood of the traffic signal being seen and obeyed and thereby mitigate the likelihood of accidents occurring as a result of failure to observe the traffic signal.